Circuit breaker



Nov. 30, 1937.

K. C. RANDALL CIRCUIT BREAKER Filed March l5, 1933 M. W #W 2 Sheets-Sheet l lNVENTOR /Gr/C /anaa/ BY o6 v ATTORN Y NOV. 30, 1937. K RANDALL 2,100,749

CIRCUIT .BREAKER Filed March l5, 1933 2 Sheets-Sheet 2 2 d AVar/C. Edna/a,

a WML@ yPlasma Nav. 3o, 1931 xm c. Randall, Edgewood. ra., assigner to Westinghouse Electric Manufacturing Com- Pennsyl pany, East Pittsburgh, rPa., 4a corporation of Application Marsh 15, 193s, serial No. 660,936

14 Claims. (cl. zoo-116)` An object of my invention is to provide a multipole circuit breaker mechanism in which all of the poles of the circuit breaker are normally actuated from open to closed position by a single operating handle, but in which an excess current in any one pole will cause that pole to open irrespective of the position of the operating handle, and irrespective of the position of the other poles.

Another object of my invention is to provide a multi-pole circuit breaker in which an individual current-responsive latch is provided for normally holding each pole of the breakerf in latched position, with the latch of each pole being capable of allowing its contact to move from closed to open position in response to current conditions in its pole, and in which a. single operating handle is used to reset to latched position any one or greater number o! poles which have been released in response to over-current.

A further object of my invention is to provide a three-pole circuit breaker which is particularly adapted for use as a main or entrance circuit breaker for a building using an Edison three-wire distribution system, due to the fact that one pole may open, if one side of the system is overloaded, without interrupting the circuits supplied from the other side of the system. This is accomplished without losing the advantages of having a single operating handle, for normally opening and closing the circuits of all three wires of the system, and for resetting any number of the poles which may have been tripped .due to excess current. l

A further object of my invention ls'to provide a multi-pole circuit breaker in which the contact arm of each pole is actuated normally fromA open to closed position with a snap action by a separate toggle linkage and over-center spring', but in which the linkage and spring provided for each of the plurality of poles are all normally actuated by ra single operating handle. Each pole-is also providedwitl a releasable trip member which is held by acurrent-responsive latch. Each releasable trip member is movable after its release independently of any movement of the releasable trip members of the other poles to cause its contact arm to move to open position independently of any movement of the contact arms of the other poles.v

'I'hese and other objects that will be made apparent throughout the further description of my invention are obtained by circuit-breaker apparatus hereinafter describedv and illustrated in the accompanying drawingsfwherein;

Figure 1 is a longitudinal section through a circuit breaker embodying features of my invention, portions of the circuit breaker being shown ink elevation; l

i Fig. 2 is a plan view oi' the circuit-breaker apparatus shown in Fig. 1, but with the housing shown in section; and I Fig. 3 is a diagrammatic view illustrating the electrical connections of the breaker with Athe 'U-shaped vbi-rnetallic thermal element electrically connected in series withV each contact, and illustrating the application of my invention to a multi-pole circuit breaker in which each pole Vby amovable contact I3 carried upon a switch arm I4 that is pivoted, at I5, upon a sheet-metal frame or bracket I6 which is mounted on the base 9 within the notch II. The switch arm Il is operated by a pair of toggle links I1 and I8, that are pivoted together by a knee pivot I9. The link I'I is pivotally mounted on a shaft 2| which is carried by the switch arm I4, and the link I8 is pivotally seated in a notch 22 of V-shape provided in a releasable carrier 23 that is pivotally mounted on the frame I6 for rotation about a shaft 24.

'I'he current responsive trip member or carrier 23 is releasably retained in the operable position shown in Fig. 1 by a bimetal thermal element 26 of U-shape and is diagrammatically illustrated in Fig. 3. An operating lever 2'I is mounted for rotation about the shaft 28 that /isxsecured to the frame I6, and is provided with links to the .made or straightened positions shown in Fig. 1 wherein the knee pivot I9 lies slightly above a line connecting the shaft 2| and the pivot seat of the link I8..

When the toggle is in the ,made position, the contact of the switch arm I4 is releasably retained in closed position, and, when the operat- 4inghandle 29 has been moved downwardly a suiicient distance, the spring 3| causes the toggle to collapse and move the switch arm I4 to open position with a snap action. By reason ofthis construction, the switch arm is actuated to open and to closed position by the over center spring 3|, when the switch or circuit breaker -32,'that is secured to its outer end, out of en\ gagement with thefree end of the carrier, 23.

This rotation of the carrier 23 about itspivot 24 .carries the end of the toggle link IB which engages the notch v22 across the line of action of the spring 3| and results in the collapse of the toggle and the opening of the contacts I2 and I3. The trip member or carrier 23 isreturned to reset or latched position by rotation of the op- -eratlng lever 21 counter-clockwise due tothe motion imparted to the carrier by the engage-` ment of the projection 40 on the operating lever 21 with the arm 4| on the carrier 23.

The bimetal element may be proportioned to release or trip the circuit breaker to open position in response to a predetermined overload or a short-'circuit condition and to retain the circuit breaker in closed position so long as the value of the current passing through the circuit 'breaker remains below a predetermined amount.

It will be understood that the bimetal element is normallyconnected in series with the circuitbreaker contacts and is heated' by the current owing through the circuit breaker contacts to the circuit to which the circuit breaker is connected. It will be further understood that the circuit breaker is trip-free of the handle and,

therefore, the handle cannot interfere with the opening movement of the circuit breaker in response to an overload or short-circuit condition,

regardless of its position, or whether it is being` handle type are utilized to form a multi-,pole

breaker, a single operating handle 29` isY provided that is connected to an insulating bar 36 which is connected to the operating levers 21 of the several circuit breakers, as indicated in Fig. 2. Since each of the breakers forming one pole of the multi-pole breaker may trip free of the handle and since each ,pole has a complete tripping mechanism, any one pole'of the breaker may trip and/causeits switch arm I4 to move to open position independently of the position of the mechanisms including carriers 23 and toggle links I 'I and I8, and the switch arms I4 of the otherpoles and independently of the common operating handle 29. Movement of the operating handle 29 counter-clockwise to the ofi position causes corresponding4 movement of each of the operating levers 21. If any pole of the breaker has been tripped, it is returned to latched position with the carrier 23 engaging the latch It is thus seen that the multi-pole circuit',

breaker of my invention has a 4single operating handle for normally opening and closing the switch arms of all poles in unison, and for resetting any one or more poles which may have been tripped, but that this/use of a single handle does `not interfere withV the ability of each pole to trip lto open position without movementvlof the corresponding parts of the other poles.

This structure is particularly advantageous for use as a7 main or entrance circuit breaker for a three-wire distribution system'where the load is connected between each outer conductor and the neutral, sincean overload on one side of the system will cause only the outer pole of the breaker to trip. This opens and fully protects the overloaded side of the system without in. any way disturbing the supply of current to the load on the other 'side of the system. Power may then be restored to both sides of the system bymerely moving the operating handle to'Y 'the 01T position, 'momentarily interrupting the 2 side of' the system` which has not tripped open,

and then moving the handle back to the on Y position.

In Figs; `1 and 2, I have shown a circuit breaker having three poles all mounted within a metal housing 31 having a coverv 38 that may be sealed in closed position and is provided with a slot 39, through which the operating handle 29 projects.

In Fig. 3, I have disclosed the manner in which a three-phase circuit breaker is arranged by-providing Vthree parallel-connected circuit-breakerunits for each phase of the circuit. The operat- 1 ing bar 36 extends across the circuit-breaker units and is connected kto each of the operating levers of the nine circuit breakers. Since the individual circuit-breaker units are all trip-free of the handle, they may trip open without aii'ecting the other circuit breakers connected in the circuit. Other forms of current-responsive devices may means movable tc open and close a circuit, a single operating member for normally moving a plurality of said switch means simultaneously to both open and closed position, springfmeans between said singlevoperating member and said plurality of switch means for causing said simultaneous movement of the switch means to take place with a snap action when moving to both open and closed position,'a plurality of trip members each responsive to current flow through one of said switch means, each of said trip members being movable to tripped position independently of movement of the other of said trip members to tripped position and thereby causing movement of one of said switch means movable to both open and closed position with a snap action to open position, each of a plurality of said switch means movable to both open and colsed position with a snap action being movable to open position upon movement of one of said trip members independently ofv movement of the other of said switch means to open position and independently of the position of said single operatingv member.

2. In a multi-pole circuit interrupter, a movable contact member for normally opening and closing the circuit through each of a plurality of l a trip memberfor each 'of said plurality oi' poles and each of said trip members controlling one of predetermined conditions in the circuit through said contact members and being movable to tripped position, current responsive means for each of said plurality of poles, each of said current responsive means upon the occurrence of -.its pole causing actuation of one of said trip members to tripped position to cause the contact member for normally opening and closing the circuit through the pole controlled thereby to mdve to open position independently of any movement of the other of said contact members'.

3. In a mutli-pole circuit interrupter, a movable contact member for normally opening and closing the circuit through each of a plurality of said poles, energy storing means for each of said movable contact members for normally opening and closing the circuit, a single operating means movable to both lopen and close all of said contact members, said operating means imparting energy to each bf said energy storing means and then causing release of said energy to simultaneously move all of said contact membersY for normally opening and closing the circuit with a snap action, a trip member for each of saidplurality of poles and each of said trip members controlling one of said contact members and being movable to tripped position, `current responsive means for each of said plurality of poles, each of said current responsive means upon the occurrence of predetermined conditions in Ythe circuit through` its pole causing actuation of one of said trip members to tripped position to cause the contact member for normally opening and closing the circuit through the pole controlled thereby to move' to open position independently of any movement of the other of said contact membersand irrespective` of the position in which said operating means may beheld.

4. In a multi-pole circuit interrupter, a movable contact member for normally opening and closing the circuit through each of a plurality of said poles, energy storing meansfor each of said movable contact'members for normally opening and closing the circuit, a single operating means movable to both open and close-all of said contact members, said operating means imparting energy f to each of said energy storing means and then causing release of said energy to simultaneously move all of said contact members for normally opening and closing the circuit with a snap action, a trip member lfor each of said plurality of poles and each of said trip members controlling one of said contact members and being movable to tripped position, current responsive means for each of said plurality of poles, each of said current responsive means upon the occurrence of predetermined conditions in the circuit through its pole causing actuation of one of said trip members to tripped position to cause the contact member for normally opening and closing the circuit through the f pole controlled thereby to move to openlposition` independently of any movement oi.' the otherof said contact members and irrespective of thev position in which said operating means may be held, and any trip member which has movedto tripped position being reset by movement of said operating means without reclosing said contact member which moved to open position upon movement of the trip member to tripped position. f

5. An electric circuit breaker comprising a plurality of contact-actuating mechanisms connected for joint operation each having its own actuating spring, said mechanisms being operable to move the contact sets to both open and closed circuit position with a snap motion, a plurality of contact sets operable by said mechanisms, a 'plurality of means to release said mechanisms on overload,

and a plurality of current responsive means to cause actuation of said releasing means.

6, An electric circuit breaker comprising a plurality of contact-actuating mechanisms connected for Joint operation each having its own actuating spring, said mechanisms being operable to move the contact sets to both open and closed circuit position with a snap motion, a plurality of contact sets simultaneously movable upon operation of said mechanisms, separate means for releasing said mechanisms upon overload, and a plurality of current responsive means to cause operation of said releasing means.

7. In a-multi-pole circuit interrupter, a mov-- able contact member for normally opening and closing the circuit through each oi.' a plurality of said poles, energy storing means for each one of said movable contact members, a single operating lmeans movable to both open and close all of said contact members, said operating means when moved in circuit closingdirection causing each of said energy storing means to move one of said contact members to close the circuit, and each of said energystoring means acting on one of said contact members when in closed circuit position to bias it'to move to open circuit position, current responsive means for each one of said plurality of poles, each of said current responsive means controlling one of said contact members', and each of said current responsive vmeans upon the occurrence of predetermined conditions in the circuit through its pole causing the contact member for normally opening and closing the circuit said plurality of contact members, said operating i member when moved in circuit closing direction causing each of said biasing means to move its associated contact member to close the circuit, each of said biasing means acting on its associated contactmember when in the closed position and biasing it to move to open circuit position, and each of a plurality of said Contact members having a normally latched part associated therewith which when latched prevents said biasing means from automatically moving its associated contact member to open circuit position, a plurality of current responsive means each normally ly latched parts for holding it-against movement and being disengageable therefrom'for initiating movement of the contact member controlled thereby to open position independently of any movement of theY other contact members, and said single operating member being .operable to normallymove said contact members to open -circuit position without causing disengagement of said current responsive means -from said normally latched parts.

9. Ina multi-pole circuit interrupter, avplurality of movable contact members for normally opening and closing the circuit through ya plurality of said poles, a plurality of separate biasing means each associated withone of said movable' contact members, a single operating member movable to normally both open and close all' of said plurality of contact niembers, saidoperating member when moved in circuit closing direction causing each of said biasing means to move its associated contact member to clos the circuit, each of said biasing means acting on its associated contact member when in the closed position and biasing it to move toopen circuit position, and each of a plurality of said contact members having a `normally latched part associated therewith which when latched prevents said biasing means from automatically moving its associated contact member toopen circuit position, a plurality of current responsive means each normally in latching engagement with one of said normally latched parts for holding it against movement and being disengageable therefrom for `initiating movement of the contact member controlled thereby to open position independently of any movement of lthe other contact members, said single operating member being operable to normally move said contact members to open circuit position without causing disengagement of said current responsive means from said normally latched parts, and the disengagement of any'one of said latched parts by its current responsivemeans causing movement of its associated contact member to open circuit position irrespective of the vposition in which said operatingmember may beheld.

10. In a multi-pole circuit breaker, a plurality of movable contacts for normally opening 4andA closing the circuit through a plurality of said poles,` a single operating member movable to normally both. open and close all of said plurality of contacts, a plurality of springs each of which biases and moves one of said contacts to closed circuit position upon movement of .said single operating member to closed circuit position,and

each of said springs exerting a biasing force when the Acircuit breaker is closed to move one of said contacts from closed circuit position to open circuit position, a plurality of latch portions each associated with one of said contacts for controlling its movement to open circuit position due to the bias of 'its spring, a plurali-ty of bimetallic members each normally engaging and holding one of said latch portions, each of said bimetallic members'beirg responsive to the current flow through one of said contacts and being movable upon the occurrence of an abnormal condition to disengage its associated latch portion and permit the spring associated with its contact to move it to open circuit position independently of the other contacts, and said "single operating member being movable to return any of said latch common handle may be held.

portions to latched engagement with their bimetallic members and being movable to normally open all of said contacts without disengaging said bimetallic members from theirlatch portions.

11.An electric\circuit breaker comprising a plurality of 'contact-actuating mechanisms connected for joint operation each having its own actuating spring, said mechanisms having a common handle and being operable thereby to move the contact sets to ,both open and closed' circuit y position `with a snap motion, a plurality of contact sets operable by said mechanisms,- a plurality of means to release said mechanisms on overload, and a plurality of current responsive means to cause actuation of said releasing means, Y,said actuation of the releasing means causing at least one of the contact'sets to move to open circuit y position irrespective of the position in which said 12. An electric circuit 'breaker ,comprising a plurality of contact-actuating mechanisms connected for joint operation each having its own Aactuating spring, said mechanisms having a common handle and being operable thereby to move the contact sets to both open and closed circuit position with a snap motion, a plurality of contact sets operable by said mechanisms, a plurality of means to release said mechanisms on over-- load, and a plurality of current responsive means to cause actuation of said releasing means, said actuation of the releasing means causing at least one' of the contact sets to move to open circuit position irrespective of the position in which said common handle may be held, 'and said common handle being operable after actuation of the releasing means to cause resetting thereof and place the circuit breaker in4 condition to be normally operated to both open and closed circuit positions by said common handle.

y 13. An electric circuit breaker comprising a plurality of contact-actuating mechanisms connected for joint operation each having its own f actuating spring, said mechanisms being operable to move the contact sets to both open and closed circuit position lwith a snap motion, a plurality of contactsets operable by said mechanisms, a plurality of means to release said mechanisms on overload, a plurality of current responsive means to cause actuation of said releasing means,

and each of a plurality of said contact sets being movable to open circuit position upon actuation of one of said releasing means without movement f other of said plurality of contact sets.

14. An electric circuit breaker comprising a iplurality of contact-actuating mechanisms connected for joint operation each having its own actuating spring, said mechanisms having a common handle 'and being operable thereby to move the contact sets to both open and closed circuitv handle, and said common handle being operable to cause resetting of said releasing means.

' KARL c. RANDALL.' 

